V

viewpoints

DOI:10.1145/1516046.1516054 Peter J. Denning

the Profession of It
Beyond Computational
thinking
If we are not careful, our fascination with “computational thinking”
may lead us back into the trap we are trying to escape.

I
n thE mIDst of our struggle to the deep questions of the field.6,9 • Is computational thinking a
better articulate why comput- • Showing that computation is funda- unique and distinctive characteriza-
ing is so much broader than mental, and often unavoidable, in most tion of computer science?
programming, a movement of endeavors—a desire to proselytize. • Is computational thinking an ad-
sorts has emerged. It is being Since starting a stint at NASA-Ames equate characterization of computer
called “computational thinking.”8 in 1983, I have been heavily involved science?
The U.S. National Science Founda- with computational science and I have My own conclusion is that both an-
tion’s Computer and Information devoted a substantial part of my own ca- swers are no. I will suggest that a prin-
Science and Engineering (CISE) di- reer to advancing these objectives. Since ciples-based framework answers both
rectorate has asked most proposers, questions yes. We are custodians of a
especially those in its CPATH initia- deep and powerful discourse: Let’s not
tive, to include a discussion of how hide it with an inadequate name.
their projects advance computational
thinking. Carnegie Mellon Universi- What is Computational thinking?

÷
?
ty’s Center for Computational Think- Computational thinking has a long his-
ing says, “It is nearly impossible to tory within computer science. Known
do research in any scientific or engi- in the 1950s and 1960s as “algorithmic
neering discipline without an abil- thinking,” it means a mental orienta-
ity to think computationally.…[We] tion to formulating problems as con-
advocate for the widespread use of versions of some input to an output
computational thinking to improve and looking for algorithms to perform
people’s lives.”1 the conversions.
Computational thinking is seen Today the term has been expanded
by its adherents as a novel way to say to include thinking with many levels
what the core of the field is about, a of abstractions, use of mathematics
lever to reverse the decline of enroll- 2003 I have advocated a great-principles to develop algorithms, and examining
ments, and a rationale for accepting approach to the perennially open ques- how well a solution scales across differ-
computer science as a legitimate field tion, “What is computer science?”4 ent sizes of problems.1
of science. This movement is driven by Yet I am uneasy. I am concerned that
four main concerns: the computational thinking movement is Computational thinking
• Bringing computer science to reinforces a narrow view of the field unique to Computer science?
the table of science (as partner, not and will not sell well with the other sci- In the 1940s, John von Neumann wrote
programmer). ences or with the people we want to at- prolifically on how computers would
• Finding ways to make computer tract. I worry that we are not getting out be not just a tool for helping science,
science a more attractive field for stu- of the box, but are merely repackaging but a way of doing science.
dents to major in and for other scienc- it with new paper and a fresh ribbon. As early as 1975, Physics Nobel
es to collaborate with. In this column, I will examine two Laureate Ken Wilson promoted the
• Resurrecting ongoing inquiry into key questions: idea that simulation and computation

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 viewpoints

were a way to do science that was not Therefore, it is unwise to pin our
previously available. Wilson’s Nobel hopes on computational thinking as a
Prize was based on breakthroughs he Computation is way of telling people about the unique
achieved in creating computational unavoidable not character of computer science. We
models whose simulations produced need some other way to do that.
radical new understandings of phase only in the method The sentiment that computational
changes in materials. In the early 1980s, of study, but in thinking is a recent insight into the true
Wilson joined with other leading scien- nature of computer science ignores the
tists in many fields to advocate that the what is studied. venerable history of computational
grand challenges of science could be thinking in computer science and in
cracked by computation and that the all the sciences. Computer science is
government could accelerate the pro- a science in its own right (see the side-
cess by supporting a network of super- bar “Computer Science as Science”).
computing centers.7 They argued that
computation had become a third leg puter science was present but was not a Is Computational Thinking
of science, joining the traditional legs key player. Computer scientists, in fact, Adequate for Computer Science?
of theory and experiment. The term resisted participation until NSF CISE In 1936 Alan Turing defined what it
“computational thinking” was com- and DARPA set up research programs means to compute a number. He of-
mon in their discussions. open only to those collaborating with fered a model of a computing machine
The computational sciences move- other sciences. and showed that the machines were
ment eventually grew into a huge In the middle 1980s, Ken Wilson ad- universal (one could simulate anoth-
interagency initiative in high-perfor- vocated the formation of departments of er). He then used his theory to settle
mance computing, and culminated in computational science in universities. a century-old “decision problem” of
the U.S. Congress passing a law fund- He carefully distinguished them from mathematics, whether there is a by-
ing a high-performance computing computer science. The term “computa- inspection method to tell if a set of de-
initiative in 1991. tional science” was chosen to avoid con- cision rules can terminate with a deci-
This movement validated the notion fusion with computer science. sion in a finite number of moves. He
that computation (and computational Thus, computational science is seen showed that the “decision problem” was
thinking) is essential to the advance- in the other sciences not as a notion not computable and argued that the very
ment of science. It generated a power- that flows out of computer science, but act of inspecting is inherently compu-
ful political movement that codified as a notion that flows from science it- tational: not even inspectors can avoid
this notion into a U.S. federal law. self. Computational thinking is seen as computation. Computation is universal
It is important to notice that this a characteristic of this way of science. and unavoidable. His paper truly was the
movement originated with the leaders It is not seen as a distinctive feature of birth of computer science.
of the physical and life sciences. Com- computer science. The modern formulations of science

Computer Science as Science

Since its beginnings in the late networking infrastructure was equal partners in the search for scientists in other fields have
1930s, computer science has a grand challenge that took new principles. So it matters discovered natural information
been a unique combination of many years. Now that this has whether computer science processes—affirming the
math, engineering, and science. been accomplished, we are qualifies as a full-fledged sixth criterion.3 The older
It is not one, but all three. Major increasingly able to emphasize science. Whether a field is seen definition of computer science
subsets form legitimate fields of the experimental method and as a science depends on its as “the study of phenomena
math, engineering, or science. reinvigorate our image as a satisfying six criteria:5 surrounding computers,”
But if you focus on a single science. Our many partnerships ˲˲ Has an organized body of which dates back to Alan
subset, you cannot express the with other sciences including knowledge Perlis, George Forsythe, and
uniqueness of the field. biology, physics, astronomy, ˲˲ Results are reproducible Allen Newell around 1970,
The term “computer materials science, economics, ˲˲ Has well developed experi- is giving way to “the study
science” traces back to the cognitive science, and mental methods of information processes,
writings of John von Neumann, sociology, have led to amazing ˲˲ Enables predictions, includ- natural and artificial.” The
who believed that the innovations. ing surprises shift from computer as object
architecture of machines and These collaborations ˲˲ Offers hypotheses open to of study to computer as tool is
applications could be put on a have uncovered questions falsification enabling us to revisit the deep
rigorous scientific basis. in the other fields about ˲˲ Deals with natural objects questions of our field in the
Until about 1990, the whether computer science is Computer science easily new light of computation as a
emphasis within the field was legitimately science. Many see passes the first five of these lens through which to see the
developing and advancing computer people as engineers tests, so the debate has tended world. The most fundamental
the technology. Building implementing principles they to center on the last. During of these questions is: What is
reliable computers within a did not discover rather than the past decade, prominent computation?6,9

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viewpoints

recognize the same truth when they say ity to take care of the concerns listed at
that computation is an essential meth- the beginning of this column. But giv-
od of doing science. In fact, a growing The real value of en the outside perception, computa-
number of scientists are now saying computer science tional thinking is all too easily seen as a
that information processes occur nat- repackaging—a change of appearance
urally (for example, DNA transcrip- is in the offers we but not of substance. Do we really want
tion) and that computation is needed are able to make to replace that older notion with “CS =
to understand and eventually control computational thinking”? A colleague
them.3 So computation is unavoidable from our expertise, from another field recently said to me:
not only in the method of study, but in which is founded “You computer scientists are hungry!
what is studied. First you wanted us to take your courses
This is a subtle but important dis- in a rich and deep on literacy and fluency. Now you want
tinction. Computation is present in discourse. us to think like you!”
nature even when scientists are not ob- I suggest that the real value of com-
serving it or thinking about it. Compu- puter science is in the offers we are able
tation is more fundamental than com- to make from our expertise, which is
putational thinking. For this reason founded in a rich and deep discourse.
alone, computational thinking seems We are valued at the table when we
like an inadequate characterization of at which we can develop various levels help the others solve problems they
computer science. of skill. Computational thinking is one care about. We are most valued not for
A number of us developed a great of several key practices at which every our computational thinking, but for
principles framework that exposes computer scientist should be compe- our computational doing.
the fundamental scientific principles tent (see the sidebar “The Great Prin-
of computing4,6 (see the sidebar “The ciples Framework”). It shortchanges References
1. Carnegie Mellon University Center for Computational
Great Principles Framework”). This computer science to try to characterize Thinking; http://www.cs.cmu.edu/~CompThink.
framework interprets computer sci- the field by mentioning only one essen- 2. Computer Science Unplugged Web site; http://
csunplugged.org.
ence as the study of fundamental prop- tial practice without mentioning the 3. Denning, P. Computing is a natural science. Commun.
erties of information processes, both others or the principles of the field. ACM 50, 7 (July 2007), 13–18.
4. Denning, P. Great principles of computing. Commun.
natural and artificial. Computers are ACM 46, 11 (Nov. 2003), 15–20.
the tool, not the object of study. Com- Conclusion 5. Denning, P. Is computer science science? Commun.
ACM 48, 4 (Apr. 2005), 27–31.
putation pervades everyday life.2 Computation is widely accepted as a 6. Great Principles of Computing Web site; http://
The great principles framework lens for looking at the world. We do not greatprinciples.org.
7. Wilson, K.G. Grand challenges to computational
reveals that there is something even need to sell that idea. Computational science. In Future Generation Computer Systems.
more fundamental than an algorithm: thinking is one of the key practices of Elsevier, 1989, 171–189.
8. Wing, J. Computational thinking. Commun. ACM 49, 3
the representation. Representations computer science. But it is not unique (Mar. 2006), 33–35.
9. Wing, J. Five deep questions in computing. Commun.
convey information. A computation is to computing and is not adequate to ACM 51, 1 (Jan. 2008), 58–60.
an evolving representation and an al- portray the whole of the field.
gorithm is a representation of a meth- In the 1960s and 1970s we allowed,
Peter J. Denning (pjd@nps.edu) is the director of the
od to control the evolution. and even encouraged, the perception Cebrowski Institute for Information Innovation and
In this framework, computational “CS = programming,” which is now to Superiority at the Naval Postgraduate School in Monterey,
CA, and is a past president of ACM.
thinking is not a principle; it is a prac- our dismay widely accepted outside the
tice. A practice is a way of doing things field and is connected with our inabil- Copyright held by author.

The Great Principles Framework

The Great Principles (GP) technologies. They can be computing. The Internet, for practices:
framework is a way to express grouped into seven categories: example, is a technology that ˲˲ Programming
computer science as a field ˲˲ Computation draws its operating principles ˲˲ Engineering of systems
of science based on deep ˲˲ Communication primarily from communication, ˲˲ Modeling
and enduring fundamental ˲˲ Coordination coordination, and recollection, ˲˲ Applying
principles.3,4,6 The framework ˲˲ Recollection and its architecture from design Computational thinking
has two parts: core principles ˲˲ Automation and evaluation. can be seen either as a style of
and core practices. ˲˲ Evaluation The core practices are areas thought that runs through the
The core principles are ˲˲ Design of skill and ability at which practices or as a fifth practice.
statements and stories about These are not mutually computing people can display It is the ability to interpret
the immutable laws and exclusive groups of principles, various levels of performance the world as algorithmically
recurrences that shape and but windows that bring such as beginner, competent, controlled conversions of inputs
constrain all computing particular perspectives about and expert. There are four core to outputs.

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